Ice Ages and The Book about Milankovitch

This is a comment on WUWT that I’m preserving here since I’m tired of needing to explain this again and again and look up the book reference each time.

E.M.Smith March 20, 2015 at 1:52 pm Edit
Yes! (To Slavatore Del Prete)

This (from a paper trying to say it was CO2, not orbital cycles, that cause the ice age / interglacial cycles):

“This makes sense in that the whole world was cold at the same time, but the Milankovitch theory should have opposite effects for the Northern and Southern Hemispheres, and thus cannot explain the synchronous advance of glaciers around the globe. ”

Is where they have gone idiotically wrong. You, Salvatore, and Data Soong, have got it right.

“They” have made the typical “noob” idiot mistake of simplification and leap to conclusion. Had they actually read about the Milankovitch cycle hypothesis they would have enough clue to know they were being idiotic.

The “thumbnail” is that first Milankovitch thought something similar, but found the data conflicted. Then he tried another approach that also failed as it was “exactly backwards”. Then he had the “Ah Ha!” moment and got it right. It is all neatly described in a history of his work that I’ll recommend below. But first:

The basic cause of the asymmetry is the land. The South Pole is all land all the time surrounded by water. The North Pole is all water all the time surrounded by land. Due to this, the South Pole is ALWAYS frozen. Always. Full stop. No melting. Done deal. (Anyone talking about the South Pole “melting” is full of it. No other option applies.) Only the North Pole can melt.

And melt it does, but ONLY when things are just EXACTLY right. We are, fundamentally, an Ice Age Planet that pops out of it just for a tiny little while and only when things are just right to melt the north pole ice. Anyone who is all worked up that the North Pole is melting is like the dog trying to sink his teeth into a car tire doing 30 MPH. If he gets what he wants he will be seriously injured and absolutely mortified. WHEN the North Pole freezes over next and stays frozen we are headed head first into that long night of deep freeze frozen ice age “pronto” with no recourse. Again: Period, full stop.

What Milankovitch figured out was that when ALL the parameters of the Earth Orbit line up just so, we barely cross the threshold for North Pole melting and poke our little frozen noses out for just a little while. Then when any of them gets far enough away from that magic alignment, it’s all ice ice baby all the time again. We are presently on the cusp of that W/m^2 rate and can be stable in either frozen or melted states depending on albedo of snow on the ground…

One other point, the key bit is NOT distance from the sun. In fact, we melt when furthest from the sun. Solar energy is not diminished worth note by distance, BUT when the Earth is at it furthest from the sun, it takes longer to make the season change happen. So when it is summer at furthest from the sun we have a few more days of summer. It is that few more days, not the simple W/m^2, that melt things and let the interglacial happen.

So, when summer in the Northern Hemisphere happens with the Earth furthest from the sun, and the tilt is maximized so polar heat is maximized, and the orbital eccentricity is maximum so we get the most added days of N.H. summer, then, and only then, can ONE pole melt, that being the N.H. pole, and allow an interglacial. At all other configurations we freeze.

(Sidebar per the 41K / 100K year problem: IMHO it is pretty easy to explain. In the past we were warmer. We could melt the north pole on lesser changes, like the 41 ky changes alone. Now we are, overall, much colder. It takes ALL the parameters being neatly aligned and that only happens on the 100 Kish year cycle. Really about 120 ky including the interglacial part… Look at the temp record and you can still see spikes up at the 41 ky cycle points, just not enough to melt the North Pole…)

FWIW, if you would understand the actual Milankovitch theory (which is unlike what most folks think it is and post about and complain about and…) there is a very nice small and readable book that explains it all nicely. It is the story of the history of Milankovitch and his work with paper and pen while in a German prison, only incidentally going into the theory and how it works, via relating what he tried and failed and tried again until he got it right. That book is highly recommended:

“Ice Age: The Theory That Came In From The Cold!” by John and Mary Gribbin.

Please, buy it and read it. It’s a wonderful tale and full of useful information for the small size and only 105 pages. You will never look at Milankovitch the same way again once you know about his life and how carefully he worked all this out. Spending, literally, years in a prison cell with plenty of time to think and nothing but pen and paper to do the work. (The Germans in that WW were not fond of his nationality…) At the end you will understand just how interglacials form, and why they are the key bit, not “why ice ages happen”… we are default ice…

If the warmistas had a clue about this they would be actively praying for “global warming”. In no more than 2000 years and potentially as short as 300 years you can kiss Canada good-by as the ice returns. New York City goes too, but a bit later as the ice takes a while to build up… And there is absolutely nothing we can do to stop it.

Now, back at this “paper”…

As they have already got it entirely wrong by saying that the hemispheres ought to be counter cyclical to each other (and completely do not have a clue that Milankovitch took that approach, found it wrong – provably – and discarded it) and are clueless about what Milankovitch actually SAID causes interglacials, the rest of their work is disposed of in the same trash barrel. If you can’t even check your references and read your citations, the rest is going to be garbage…

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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40 Responses to Ice Ages and The Book about Milankovitch

  1. Power Grab says:

    Ordered the book. Thanks!

    I’m always looking for concise, digestible books that I can recommend to friends. I don’t rub elbows with many scientific types. Most of the time, when I talk about things like this to my friends, their eyes glaze over!

  2. jeremyp99 says:

    Thanks for the tip – I’ve also ordered it, to add to my growing collection of books about past and present climate. When my warmer friends froth at me I ask them what they have read about climate. None of them have read anything. Yet they know they are right. Hmmmmm.

  3. jim says:

    Loved your ending “If you can’t even check your references and read your citations, the rest is going to be garbage…” That is a world of truth.
    With an new publication, or an old one, the title is not enough except to get in the news. The abstract is little better, often the truth is in the last graph or data table, and it shows the entire article to be a desperate attempt to make the data fit a preconceived theory, and the fit is shakey at best, or just wrong.

  4. p.g.sharrow says:

    @EMSmith; “Maybe only 300 years to falling off the Ice Mountain cliff!”

    300 years to save Mankind, Emmmmm…………. sounds doable to me. :-) We just need to get past these Ecoloons that want to save the Earth from man, A thing that doesn’t need their help.

    A true space drive, space borne manufacturing to create a few 100sq miles of mirrors should be enough to tip the balance. Yah think! Guess I should get back to work on that. ;-) pg

  5. Graeme No.3 says:

    Thanks for the tip. Have ordered book.
    Will be interested how it solves the 10,000 year problem.

    Incidentally, I notice in the chart of temperature over the last 5 million years e.g. in
    shows not only lower minimums but wider ranges. Knowing nothing about it, can I rush in and ask “is this a prelude to a change?” or are we on a ever downward slope to snowball earth?

  6. Martin Clark says:

    Printed version is a bit expensive, but there is a 2014 Kindle version available.
    Very readable. Btw – Milankovitch was only in jail for about 5 months – not bad by the standards of the time :-)
    It’s the sheer scale of the work, pen to paper calculations, that got me. As a practising engineer I guess he had a slide rule, but all the same – his calculations were correct, and didn’t get refined further until the 60s & 70s.

  7. Ian W says:

    The problem is that as the Earth’s climate gets closer to the glacial ‘attractor’ it will take less and less of a butterfly wing flap to flip the climate to orbiting the glacial rather than the interglacial attractor. It may not need the large perturbation of a Bond or O-S event. Forecasting chaotic system behavior is not a matter of simple linear interpolation.

  8. Gary says:

    And I would suggest Ice Ages: Solving the Mystery by John and Katherine Imbrie for a readable narrative of the CLIMAP project’s support of the Milankovich theory in the 1970s.
    There’s a wee bit of CO2 might cause a super-interglacial, but mostly as a passing nod at a time when the science was young and relatively purer than now.

  9. Another Ian says:


    Very O/T but check this out

    “Transcript Station:
    Program: The STREAM Time:7:06 AM
    AL JAZEERA Summary ID:W00059934129


    MORRISON: I’m sorry. I have to interrupt here.

    I’m sorry I am not going to sit here and listen to people stupidly suggest that the French or the magazine or anyone else brought this on themselves.

    Are you for real? ” ”

    DuckDuckGo seems to confirm it happened

  10. David A says:

    E.M.; off topic question on your excellent “There is no Energy Shortage post. I am having trouble finding out how you arrive at one assertion… “Nuclear has about a 10,000 year lifetime from the Uranium in present mines on land before we have to get fancy…”

    Thanks in advance.

  11. cdquarles says:

    Let me see if I have this straight. Earth’s obliquity is 23.5 +/- 1 degree of angle and its variablility isn’t a smooth sine curve. We are now at 23.44 or so degree tilt and it is dropping. Earth’s eccentricity is 0.016 or so and also dropping (orbit becoming more circular) and this also varies between more elliptical and less elliptical shapes. We have precession of the equinoxes = precession of the solstices added to the above, of which some contributes to the precession of the perihelion and aphelion. We also have continental drift rearranging the crust and placement of oceans and continents. And I’m supposed to worry about ‘climate’ when it is the weather that I have to be fruitful and multiply in?

  12. cdquarles says:

    EM, I have a question. Have they changed the geological definition of an Ice Age? If not, given that there is still perennial ice on this rock, are we not now in an Ice Age? /rhetorical.

  13. RobL says:

    Actually there’s tonnes we can do about it, I’ll be very surprised if we tolerate another ice age.

    Pumping vast quantities of warmer sea water to poles would do the job at very little energy cost (on order of million to 1 in pumping energy input to heat delivered)
    More heat input via orbital mirrors.
    Albedo altering balloons in polar stratosphere.
    Import a whole lot of Nitrogen or Argon to increase atmospheric mass, 1% more mass (~5e16kg, a sphere of LN2 50km diameter) increases ground temps by about 0.6°C, simialr mass of Argon would probably be closer to +1°C.

    Why has the earth been getting cooler as the sun continues to warm up (as do all stars in the main sequence)? Is it longer day caused by slowing earth, or loss of oxygen and nitrogen from biological and chemical processes into the ground (or space)? Quite a lot of evidence that prehistoric atmosphere was much thicker (like existence of 250-500kg 10-12m wingspan Quetzelcotalus)

  14. Ben Wouters says:

    “The South Pole is all land all the time surrounded by water. The North Pole is all water all the time surrounded by land. Due to this, the South Pole is ALWAYS frozen. Always. Full stop. ”
    Depends on the timescale your considering.
    Antarctica settled at its current position some 80-90 mya. At that time the deep oceans were around 18K warmer than today. At that time we only had some gletchers in the Antarctic interior.
    It took some 50 my of cooling down of the deep oceans before around 34 mya a dynamic East Antarctic ice sheet (EAIS) developed, presumably similar to what we had the last ~2,5 million years in the NH, driven by the Milankovitch cycles.
    Around 16 mya the EAIS became permanent, and the dynamic west AIS developed.
    Antarctica has been completely covered with ice only the last ~2,5 my.
    Question is whether the NHIS will become permanent as well with possible further cooling of the deep oceans.

  15. Richard Ilfeld says:

    Failure to cope with the next ice age, if failure is the outcome, will be political, not technical.
    The amount of heat energy necessary to render small land areas livable and concentrated agriculture possible is within reach today. The glacial penetration is likely going to be between the Canadian border & the Ohio river (in the US). Below that, we have to fight cold but not ice.
    Plenty of room to manage. What I wonder about is the probability that we will ignore the useful in an attempt to do the impossible — like “saving” Boston, or, for that matter, Toronto. I’m not sure the problem would be heat, but melt — where would the water go if the surrounding ice is a 1000 meters or more thick?

  16. Soronel Haetir says:

    So what we need to do is reconnect Antarctica and South America and so break the circumpolar current. Easy peasy.

  17. J Martin says:

    The long term future for the planet is surely a snowball earth as the rate of rotation slows and we lose atmosphere. I suspect we can’t do much about the rate of rotation, 10 jet engines anchored to the ground and ditributed round the equator perhaps, but how could we add atmosphere ? Capture a suitable asteroid ? Would using nuclear power stations to heat the sea to fend off a glaciation simply increase snowfall rates instead ?

  18. J Martin says:

    Close the gap between Antarctica and South America or enormously enlarge that canal between North and South America ? Or reduce the restrictions in the sea north of the UK that Vukcevic thinks are involves in slowing the current that allows glaciations to get going.

    Apart from sulphur and co2 do volcanoes add any useful amounts of other gases ?

  19. punmaster52 says:

    So you are on that, Soronel, and I can go back to my cinammon roll and coffee? Good. Thank you.

  20. Power Grab says:

    I keep puzzling over the phenomenon of how the earth is warmer when it is farther from the sun. It seems counter-intuitive, to say the least. But let’s assume there is a neutron star in the center of the planet. There’s some source of heat, I’m thinking. I’m wondering if magnetism from the sun helps keep it contained. (You can contain some energy sources by keeping them confined inside a magnetic field, right?) But when we are farther from the sun, and the influence of the sun’s magnetism is less, perhaps the energy from within the planet is released in greater amounts. So it’s warmer, at least in the parts of the planet that have more hours of daylight (i.e., the NH).

    On the other hand, as the earth gets closer to the sun, and its influence increases, is that keeping the neutron star’s energy contained more securely, letting the planet cool more as it gets closer to the sun? (again, still thinking of NH, or where the are fewer hours of daylight) But at the same time, does coming closer to the sun help “re-charge” the energy source inside the earth?

    Then there’s the difference between how dry land and water (brine) react to the sun’s energy fluctuations. Brine conducts electricity more easily; so is it easier for it to stay liquid (as opposed to how dry land gets frozen over while exposed to essentially the same energy fluctuations)?

    Well, since the sun’s magnetic field has lessened, if it stays reduced, will that be like the earth is always at its farthest distance? Would that mean we would get warmer and stay warmer? Or does it finally lose enough energy from within and start to freeze over everywhere except near the equatorial latitudes because it no longer gets re-charged by the higher levels of solar energy that it used to get exposed to?

    Was the step-down in 2008 actually the tipping point, where the loss of energy from within the earth no longer gets elevated to the point where it can dependably melt NH ice?

    I’m sort of thinking out loud here. Help me out.

  21. Robert Austin says:

    Power Grab,
    From the gravitational force at the surface of the Earth, we can definitely say there is no neutron star at the centre of the earth. Back to the drawing board.

  22. Power Grab says:

    I don’t really understand the concept anyway, but it was a starting assumption. What does control the flux of the energy that comes from inside the earth? It’s not constant, is it?

  23. Ben Wouters says:

    Power Grab says: 25 March 2015 at 11:24 pm
    “What does control the flux of the energy that comes from inside the earth? It’s not constant, is it?”
    Not being a geologist I’ll give it a go anyway.
    Earth is a planet consisting of molten stone, with a core of molten metal.
    In its early years, before a crust formed, the surface was magma, radiating away like crazy.
    Today a crust holds all this energy more or less in check, allowing a flux of ~65 mW/m^2 for continents and ~100 mW/m^2 for oceanic crust.
    If all the crust was like oceanic crust, no oceans and atmosphere and no sun to heat the surface, this would result in an all around surface temperature of ~50K (depending on emissivity) to radiate this 100 mW/m^2 directly to space. This is pretty much a constant flux.
    In reality on continents the flux mixes with the solar warming and has not much effect.
    In oceans the flux warms the deepest waters and this bottom warmed water can only reach the surface were no solar heated surface layer is present.
    Another form of geothermal energy is magma erupting through the crust.
    At spreading zones this seems a small but reasonably steady flux.
    Different story are mantle plumes, which can extrude gigantic amounts of magma.
    Biggest one we can still find evidence of is the Ontong Java Plateau, some 100 million km^3.

  24. E.M.Smith says:


    I think you will like the book. Well written and easy to read. Short enough to finish quickly, but humanly engaging at the same time. Covers how an Ice Age Glacial / Interglacial cycle works by going step by step through the ideas that were tossed out, getting closer ( like a mystery novel ) and then succeeding…

    BTW, not a neutron star, but quite likely a fission reactor. There’s a decent theory on that by some guy who’s name I’ve forgotten ;-) Handles the “excess energy” of other planets too. (Saturn, IIRC, radiates more than arrives from the sun…) Just assume there is U and Th in the debris that formed the planet, and that being heavy it sinks in the molten blob until enough concentrates for a ‘natural reactor’ to form. That keeps the core liquid and the planet hot for a long time. It may have some oscillation modes (nobody is sure…) where reaction products accumulate to “poison” levels and the reactor slows / halts. Those light products (and their magma) rise and are replaced by descending magma without them, and the reaction resumes.

    Only one small problem… The “right amount” to make this works only lasts about 4 to 4.5 Billion Years and then that U is used up and the reactor stops. That’s “about now” geologically… WHEN that happens, the core eventually solidifies and our magnetic field largely ends (the dynamic part from swirling liquid metal ends and a residual in the solid is too weak to matter much). So figure on atmosphere stripping and ocean loss along with ocean turning to solids (i.e. salts and ice) as we become Mars like.

    That same process, run on a smaller planet that runs out of fuel faster is very likely what happened to Mars, BTW. Also, it looks (now) like our planet has a solidifying core. “They” keep changing what they think, but last iteration I read had a solid inner core and a liquid outer core, then liquid stone then plastic stone (mantle area) then bits of magma and finally crustal areas (or something like that… like I said, they keep making up new patterns…) So there’s a reasonable chance we’re already in the cool down phase. Or not… we still have He isotope ratios and some other indications of a reactor… but those could just be left over migrations upward…

    One other point: It isn’t clear how much air we had “in the past”. There are a couple of things that point to “more atmosphere” in the past; and that would mean warmer (due to your favorite theory from {radiative gasses like CO2, simple lapse rate / compression heat, thicker troposphere slowing convective transport, whatever…} and likely wetter globally. My favorite lines of evidence are giant dragonflies and pterodactyls. The wing loading on pterodactyls is too high for them to work in present atmospheric levels, so folks have postulated thicker air (and / or insane levels of muscle strength and wing tissue toughness…) though it’s the Dragonflies I like. Insects pump air through their bodies via tubes that must pass through their joints. This limits their size (and is why we don’t have 10 foot long ants today…) As body size increases, demand for O2 goes up as the cube of the linear dimension, but the air passage only gets greater in diameter as the square. At some point that s^3 demand exceeds what the s^2 oxygen can deliver and you top out in size. For modern insects, that’s about 3 inches long (or less). So how did the 3 FOOT long dragonfly fly? Hmmmm…. More dense air solves that one. (The competing thesis is that insects are small due to predators eating the big ones… I think anteaters and people eating termites shows that small is not the needed bit… and we don’t eat Goliath Beetles… )

    At any rate, the point being that we know very little about how much air we had in the past, or anything at all about how much we will have in the future. We do know we lose some every year, but don’t worry, more comes from {somewhere} via the known {magic happens} processes of {something}… and we’ve no reason to worry about it ;-) Likely not a problem for a few hundred million more years….

    Per Brine:

    Not related to electrical conductivity. See all the frozen brine at the North Pole. What happens is that water moves very easily, so the oceans tend not to freeze as the water gets cold, sinks, and is replaced by warmer water coming up from the equator. That’s what keeps the oceans liquid. Now an interesting thing happens when it DOES freeze. At the N. Pole (and over water at the S.Pole) when sea water freezes, it preferentially freezes out fresher water leaving a very salty very dense brine that sinks. That, then, lets that ice hang around on the surface until blown by wind to warmer places and / or warmed by liquid water from the tropics making to the ice. Think ice bergs. There’s a fascinating video of one of these brine columns sinking to the ocean floor under an ice shelf in Antarctica. As it hits the floor, it dilutes and freezes, trapping all sorts of things in ice (like starfish). An icy ‘finger of death’ from above. Colder than the freezing point of the regular ocean water (that is almost freezing) so it can push it over the edge into frozen on contact… (Eventually warmer waters from nearer the equator melt the ice formed…)

    So, essentially, it isn’t about electricity, it’s about mobility of water under influences of density changes and salinity changes and the peculiar way sea water forms ices and separates heavier brines.

    Per mag field loss:

    Don’t worry. Happens all the time. Another one of those absolutely natural things that folks like to make up panic stories about. MOST of the time the loss / gain cycles don’t make a full on mag field flip, so don’t show up in the “history of magnetic field flips” in solidified magma. Too small, too short, or too local to make that big a dent. These are called “excursions” as opposed to the more sexy (i.e. bigger, more active, and a little bit scary) “reversals”. See:

    A geomagnetic excursion, like a geomagnetic reversal, is a significant change in the Earth’s magnetic field. Unlike reversals however, an excursion does not permanently change the large-scale orientation of the field, but rather represents a dramatic, typically short-lived decrease in field intensity, with a variation in pole orientation of up to 45 degrees from the previous position. These events, which typically last a few thousand to a few tens of thousands of years, often involve declines in field strength to between 0 and 20% of normal. Excursions, unlike reversals, are generally not recorded around the entire globe. This is partially due to them not being recorded well within the sedimentary record, but also because they likely do not extend through the entire geomagnetic field. One of the first excursions to be studied was the Laschamp event, dated at around 40,000 years ago. Since this event has also been seen in sites around the globe, it is suggested as one of the few examples of a truly global excursion.[

    So we had a “big one” (as excursions go) only 40,000 years ago and everybody seems to have come through it fine… We are likely having one now as the field off S. America is anomalous and off Bermuda there are places where “loops” of magnetism reach the surface and cause compasses to be a bit wonky (sometimes). Thus the “Bermuda Triangle” stories. Not a big deal, really, unless you are depending on a magnetic compass to get you to land…

    So when we make a model of a planetary mag field (via a large ball of liquid metal – mercury – being spun) it is unstable. Some flips happen, and loops of one polarity pop out here and there, then sink. Just on the scale of the Earth, this dynamic takes thousands of years to play out, so any given society thinks the mag field is relatively stable and constant. It isn’t, and hasn’t been.

    Right now we are on track for a geomagnetic “excursion”, and mostly it will just mean “northern lights” at odd latitudes and navigation via compass will be more of a challenge (so use the stars or your GPS…). Might cause some small changes of weather, but since weather is mostly driven by latitude, distance from water, and local geography (elevation, mountains, …) it can’t do much. Maybe shift the jet stream pattern a little, or slightly change rainfall patterns. (IMHO, of course).

    So nice “thinking out loud”, but most likely not what happens. (Or I could just be spouting “accepted dogma”, so keep thinking out loud as it is a good skeptical thing to do to challenge the dogma and make me state my assumptions… that might be overturned tomorrow when “they” make some new pronouncements about the earth core structure or magnetosphere or…)

    As this comment is a bit long, I’m going to have my morning coffee and come back to the rest… hope it was helpful (in a not quite fully caffeinated way ;-)

  25. E.M.Smith says:


    Interesting observation on the “well read” vs. the “Well… Read?…” groups…


    I’d go for “just wrong”. I usually read the abstract first, then the conclusions / discussion, then back up for the rest. Reads more clearly that way… and you find the BS quicker.


    Nah… just work out a bit of control on gravity so we can move the planet a bit closer and make the orbit more like we want… oh, and shift the tilt… ;-)

    FWIW, a glacial episode isn’t the end of life as we know it. Just moves civilization closer to the equator. Florida, for example, gets about 3 x as wide. Probably big enough to hold all the Canadians presently slammed up against the border longing for warmth ;-)

    So mostly we just need to move to lower elevations (that 400 foot or so that are presently underwater as ‘continental shelf’) and more south. I’m up for Florida, or maybe Brazil…

    @Graeme No.3:

    The 10,000 year problem? Slipped a decimal? If you mean the 100,000 year problem, don’t think it does. Ends with Milankovitch (as it is his history) not the following critiques. IMHO the 100,000 year problem is solvable either of 2 ways.

    1) It isn’t a problem. We got colder and the 40,000 year cycle can’t bust us out any more unless the 100,000 year aligns. (it isn’t an exact cycle anyway, and has gaps)

    2) Our projections of exact orbits and tilts millions of years into the past are off. Something changed (likely both the tilt and the degree of non-circular) due to some external actor be it passing star, planet interactions, comet strike, or who knows what.

    @Martin Clark:

    I guess I need to re-read it. It’s been a few years. I thought he was in jail longer (two times?) but I’ll need to look it up. At any rate, the calculations took years…

    @Ian W:

    We are already at the W/m^2 that lets us be stable as ice or melted. It’s just a matter of a small nudge now. That’s one of the things that warmers like to misunderstand to slam Milankovitch (as only CO2 can matter in their world…). They point out the instantaneous W/m^2 and say “See, it didn’t melt” or “See, we aren’t frozen” and miss that this system as hysteresis in it and tends to lock up in a state until the counter force is large enough to cause the abedo flip and ocean current rearrangement. Then it’s the other state until “enough” counter force accumulates….

    IMHO we almost did the flip in the LIA and the next 1/2 Bond Event cycle puts us over the edge. That ought to be in about 300 years. I hope. (The alternatives are that the LIA was a 1/2 Bond Event and the next full on is due, well, now. 540 AD + 1470 AD = 2010 AD more or less. Or that the next one won’t be quite enough, and we get to move out to the 300+1470+2010 range at about 4000 AD, or about 2000 years more. Maybe. IFF we are very very lucky.

    Or it might just snow too much in the Eastern USA for a couple of winters and start the feedback at the same time the Gulf Stream heads a bit more south and we are already headed into it… Since we are in the bistable zone, any outcome at any time is a possible.


    I think I’ve read it. ( I’ve read something by “Imbrie and Imbrie”… ) and it was good. I really need to unpack / resort my library…

    @Another Ian:

    I’ll look it up a bit later. FWIW, I find Al Jazeera generally a fast and good source for international news (while Fox is nattering about internal US politics and CNN is doing the Reality Star Du Jour and BBC is running Dr. Who… or climate propaganda ‘news’… Al Jazeera will have straight news on, though it repeats through the day. The one exception being that they take a Muslim POV on things middle east or “terrorist” related. Frankly, I find that a useful counterpoint to the general US news flow. It lets me see inside the Islamic POV a bit more.

    You do get great film from inside various Muslim areas at war since most of the time the Al Jazeera journalists can act as “fellow travelers” and be (reasonably) safe when CNN and Fox would just be hamburger and depend on cell phone videos. Then it is up to you to interpret the videos and filter the commentary as you deem needed.

    In short: ANY news can be helpful, if you don’t just take it at face value…

    @David A:

    Likely I need to flesh that out some. It was a common number some decades back when reprocessing was assumed to be in the mix. Now you will often hear 100 years (or less) from the Eco-Chicken Littles of the world. That’s based on non-breading once-through and no reprocessing recycle. The 10,000 is a SWAG (Scientific Wild Ass Guess) based on reasonable guesses as to total U available (“ultimately recoverable resource” I think it was) used in breeders (so the non-boom-stuff also is fuel) and reprocessed. The reality is that it is likely more than that as even very low grade stuff is economically usable once the good stuff runs out. 2 examples that are presently NOT considered even as a ‘resource’.

    1) Granite. Has enough U in it to be more fuel / ton than coal. (And the source of much of what washes into the oceans where we can easily and economically extract it already, so we don’t really need to mine and extract from granite…)

    2( Coal, where there is more energy in the U in a ton of coal than in the coal. Which also means all those coal ash pits are a Uranium Mine if we ever wanted more.

    So the 10,000 years was from formal estimates (some government study a couple of decades back) from known land sources of ore (i.e. not counting granite and coal and related) but in the scenario of breeders and reprocessing. Exact reference would take digging.


    There’s an interesting point you raise. On the one hand, we are dealing with a 26,000 year cycle at the very shortest, and a 40,000 year as the next nearest, and a 100,000 ish as the one that matters most, so it is a very long time frame issue and not really worth worry. I’m fond of pointing out that once the ice starts forming, it takes 100,000 years for the mile high glacier to fully develop and reach New York. Take the distance from Greenland (the remnant) to N.Y.C. and divide by 100,000 years, you get about 800 FEET a year of advance. You can literally outrace the advancing glacier by walking south 800 feet once per year and setting up a new camp… Call it Glacier Solstice Day or something…

    OTOH, to your second point, we ARE presently in an Ice Age. The term Ice Age has a formal definition that is long periods of periodic icing (glacials) and short melting (interglacials) and we are presently in an interglacial inside and extant and ongoing Ice Age. Unfortunately, in common usage, many folks call a Glacial an “ice age” and confuse things. For that reason, I typically try to say “Ice Age Glacial” when talking about an iced up period during our present Ice Age. (The prior Ice Ages were a very very long time ago… Nir Shaviv has what I think is a good explanation of why Ice Ages (formal meaning) come and go here:
    while Milankovitch has a decent explanation of why interglacials form in our present Ice Age.

    Now, keeping those straight…

    Our present interglacial has run about 12,000 years and they typically last about 10,000 to 12,000 years…. so we ‘are due’ for a dive into cold. Yet… most of them are very rapid peaks and rapid ‘smack downs’. Hotter than we got, and cooling more rapidly at this point. IMHO this is due to a large “rock fall” from space smacking the ice in Canada and melting it early. So we didn’t get as hot, so we didn’t drop as fast, and have not had overshoot into rapid icing again as quickly. covers the impact idea in much depth.

    Now if you measure the width of the other interglacials at our height (temperature) you get a width that is almost exactly the same as what we have now. Hmmmm…. So the Younger Dryas just peak clipped our overshoot and gave us a more mellow 10 ky. OK… Then a close up of the present Holocene shows a rounded top and steady (slightly accelerating) cooling to now (with largish wiggles from other causes). My take on that is we are presently on an up-wiggle out of the LIA and rolling over into a down-wiggle. Each down step colder then the prior in the ice record. That means our nest “Little Ice Age” may well be a medium ice age. And that means colder in NYC now than it was in the 1600s when the water froze and folks could walk to the islands…

    Which all means we can have rapid onset of COLD with 800 ft / year linear advance of the glaciers… and still be frozen compared to now. Think “year without a summer”… or “1800 and froze to death”.

    That means that while you don’t need to worry about the arrival of the “next Ice Age”, you do need to worry about the arrival of the next Glacial a tiny bit, and you really do need to worry about the arrival of “2000 and froze to death” right now. (Well… really in about 2020, but in geologic terms that’s ‘right now’ ;-)

    Hope that helps more than confuses…

    @Rob L:

    I’d vote for “burn all the coal” as a nice atmosphere density increaser… and then convert the limestone to calcium… and then…

    Though frankly I expect the arrival to be so slow that people just move to the expanding land in the more tropical areas as the ocean drops. If each generation just moves 800 feet / year, or about 24,000 feet / 30 year generation, call it 5 miles a lifetime give or take; more southward, we stay ahead of the ice. During “1800 and froze to death” we had wholesale movement from the New England area to Oklahoma and the plains States. That was way faster than needed for outrunning the glacial. Remember that while it might get cold quickly, folks do live in Siberia and Finland (and North Canada…) so we don’t need to move on the first cold spell. Over time the movement needed is slower (much much slower) than recent migrations from Europe to the Americas during the LIA (when my Irish ancestors and my Amish ancestors arrived…)

    So we have plenty of time to just ignore it and learn Portuguese while taking the kids to Brazil…

    @Ben Wouters:

    Yes, it depends on the time scale. A common issue in geological time thinking. I’m looking at the Ice Age Glacials during our present Ice Age as Milankovitch worked out (that being the topic of this posting). Yes, if you move millions and millions of years out of that time scale, you can get Antarctica to drift off the south pole. I’m not on that time scale. On the time scale of just a few million years, it is stationary and it’s frozen all the time.

    @RIchard Ilfeld:

    Keep your time scale in mind. Take a look at the ice volume (upside down) on this graph:

    It takes a full 100,000 years for full ice to develop and it is wiggly, but on a linear average slope. It would take centuries for significant ice depth to build up at Boston. (Toronto, now that’s another thing ;-)

    There’s more than enough time for us to evolve into a new species by then… Neanderthals were around during the last Glacial…

    But yes, nuclear powered greenhouses and nice hyperinsulated structures would even let you live in Antarctica, if you so desired.

    @Soronel Haetir:

    My favored one is to cut through the Panama Isthmus with some nuclear dredging and make the Panama Canal really really wide… that lets Pacific hot water into the Atlantic and adds more to the flow to the north pole. Minimal work for maximal gain. Might need to teach some Panamanians how to speak Portuguese though ;-)

    @J. Martin:

    I see you like the Panama BIG Canal idea too ;-)

    FWIW, once volcanism stops and subduction ends we lose CO2 recycle via calcium carbonate decomp and we lose water recycle via hydrated rock dehydration and the whole place goes Mars like (frozen, dry, and airless). Pray for ongoing volcanoes…. just don’t toss in any virgins… leave them angry and erupting…

    As for adding new air: Just send ships to the asteroid belt and let them set up giant snowball factories. Send a stream of ice balls at the Pacific to replenish the water. Trees can turn it into air…


    Nice exposition on the crustal heat rate. Only place it really matters is at volcanoes and mid-ocean ridges, IMHO. Oh, and in subduction zones as a rock recycle water and CO2 generator.

    Maybe we need to find some high U containing asteroids and start feeding large batches into subduction zones to keep our core reactor fueled for a few more billion years…

  26. RobL says:

    Answering my own question;
    estimated 1e15 tonnes of Nitrogen has been moved into the crust by biological processes – with estimated 400million year residence time. about 4e15 tonnes in atmosphere. So air has maybe 20% reduction in Nitrogen since nitrates and ammonia started getting locked away, which would reduce global temperatures by about 10-15°C, perhaps leading to ice ages now.

  27. RobL

    ice ages same as the phony ”global” warmings, are just that, PHONY. If you intend to scare us with ice age or global warming – you must say: BOO!!!

  28. Ben Wouters says:

    “Yes, if you move millions and millions of years out of that time scale, you can get Antarctica to drift off the south pole.”
    Suggest you re-read my comment:

    Antarctica settled at its CURRENT position some 80 million years ago, yet it took another 50 million years or so before dynamic ice sheets started to develop on East Antarctica.
    Just ~3 million years ago Antarctica developed its current total ice cover.

  29. Ben Wouters says:

    Nice exposition on the crustal heat rate. Only place it really matters is at volcanoes and mid-ocean ridges, IMHO.”

    Imo the geothermal flux is essential in maintaining the thermohaline circulation.
    Without warming of the bottom waters, the deep oceans would fill up pretty fast with the cold, dense Antarctic Bottom Water (AABW) and the thermohaline circulation would stop.
    Given the slow cooling rate of the deep oceans it seems save to state that the warming by all geothermal and the cooling at the surface (mostly) around Antarctica are almost in balance.
    Last 85 million years on average slightly more cooling than warming.

  30. Larry Ledwick says:

    Regarding the onset of general glaciation at lower latitudes (IE Chicago etc.) you might look at perennial snow cover in the mountains as a model of how it will occur. In cold wet years in the Rockies and other mountain ranges you see large accumulations of snow in slightly sheltered locations that lingers long into the summer months. Sometimes almost to first snow of the next season. In the 1970’s we had skiing in some locations here west of Denver on July 4th. It was cruddy wet snow but it was still skiable. These snow fields come and go as long term proxies for the combined effects of precipitation and temperature (they respond to both, not just temperature.)

    These slightly protected locations are typically north and north east facing slopes that tend to get less late afternoon sun than other terrain, and due to prevailing winds tend to get drifting in spring storms, causing the snow field to melt slower and last longer in the summer months. Even when several feet deep it is still mostly heavy wet snow with some hard crusting.

    This should be how the local glaciation starts. Such slightly protected locations will start to see long lasting snow fields that fail to melt each summer, and gradually thicken over decades. This would continue for several human life times as the snow fields get gradually larger and more resistant to occasional hot dry summers. As a result humans will naturally move away from those locations over generations of time. The snow fields would be good summer long sources of water for local vegetation so they would be good “self watering” pastures in the summer long after they were unsuitable for conventional warm climate agriculture.

    In the northern reaches, as average temperatures and snow accumulation increases, eventually you would see a creeping advance of tundra and sparse forest advance southward over hundreds of years. A theory advanced in the 1970’s suggests it could also see periods of snap like advance due to “snow blitz” events.

    In this scenario as the climate gets closer and closer to the critical cooling threshold, at some random point conditions will conspire to create a massive blizzard like event (like the blizzard that killed so much livestock up in the dakotas in 2013 — which is along with drought in Texas primary reason for current high beef prices.)

    You have a horrendous late spring blizzard that dumps 3-6 ft of snow, and in the places where it drifts deeply, on sheltered slopes starts the formation of perennial snow fields.

    Get a couple of those winters back to back and you will have mass migration out of the area and abandonment of properties (much like the dust bowl depopulated south eastern Colorado, parts of Kansas, Oklahoma and Texas in the 1930’s)

    It will not be a case of a 600 foot thick wall of ice advancing toward a major city but a case of a nearly abandoned decaying city like Detroit which has perennial snow accumulations in locations like the north side of buildings gradually becoming a snow field with shattered buildings poking up through the snow banks. People will have long past moved out of the area and only the hardy frontier types will linger a bit longer and become the seed stock for a population that lives near the zone of perennial snow fields and what will in a few 10,000 years in the future be glaciers.

  31. punmaster52 says:

    So, Larry, you are saying move out of Detroit now and avoid the rush in 500-600 years?

  32. J Martin says:

    If Uranium in the molten part of the core has about run out then whether the core remains molten will depend on how much Thorium there is down there. Can we manufacture atmosphere ? We could separate oxygen from water, and find a find a way to encourage volcanic activity.

  33. Power Grab says:

    Robert Austin, Ben Wouters, and EM: Thanks SO MUCH for your kind replies. I will continue to read and study about the things you have mentioned.

  34. Power Grab says:

    P.S. @EM: You are right about the skeptical angle I am approaching these things from. The older I get, the more I see we have had numerous myths foisted on us about things that should be treated like hypotheses. Instead, they are presented as set-in-stone dogma. I am developing a very low tolerance for that sort of thing.

    I keep coming back around to the idea that, since no one was there to witness how things came to be, and no one has been to the center of the earth, and since the tools they use for developing their arguments are only available to those within the “priesthood”, and the predictions they make are failures more often than not, it is much more entertaining to turn the dogma on its head. For example, rather than claiming that carbon dioxide causes temperatures to rise around the planet, let’s notice that much of the data shows the opposite: carbon dioxide levels rise ~800 years after temperatures rise.

    I could really get into rant mode on these issues. At this time, however, I will resist the urge.

    I am extremely grateful to you and the readers of this blog for allowing me to raise my amateurish questions. I’m sure I will continue to synthesize peculiar combinations of causes and effects for the things that puzzle me. Thank you for allowing me to bounce my thoughts off you all!

  35. Larry Ledwick says:

    Power Grab sometimes the untainted observations of the new guy, are very useful questions as they many times cut to the core issue without getting side tracked by that dogma you mention.
    Having no preconceptions can lead to new fresh insights and probing questions, never stop asking questions when that question mark just refuses to go away no matter how you puzzle over the issue. That means one of two things usually— .
    The description is muddled and unclear, or they are trying to bury the fuzzy parts in bs and hope no one notices.

  36. Power Grab says:

    @ Larry Ledwick: Thanks for the kind reinforcement and encouragement.

    I think I’m rather like the little kid in the story about the emperor’s new clothes, who just pipes up what he sees. :-)

  37. Ben Wouters says:

    Power Grab says: 30 March 2015 at 6:47 pm
    ” it is much more entertaining to turn the dogma on its head.”

    The whole idea that the tiny layer of air around the earth can increase the average surface temperature around 90K above the moons average surface temperature is totally insane imo.
    Especially CO2 warming the deep oceans is total nonsense.

    Actually CO2 cools the surface (a little) during daytime by preventing solar IR from reaching the surface.
    just above 2000 nm

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